The present invention relates to improvements in connections for vent pipes in roofs.
Typically, vent pipes in roofs for residential buildings are provided to permit the escape of gas-phase materials. Indeed, most residential building codes require that building's sewer connections be provided with vents so that obnoxious and potentially hazardous fumes are not released into the household. These connections are typically achieved by extending a pipe to the roof that opens upwardly to the sky, with a seal around the outside of the pipe to prevent rainwater or other precipitation from entering the building from the outside of the pipe. However, no provision is made to prevent rainwater from entering the pipe itself, the assumption being that since the pipe is connected to the sewage system, little harm is done in permitting leakage into the pipe. A typical installation and flashing of this type is shown in U.S. Pat. No. 4,526,407 to Kifer.
However, vent connections of this type have numerous drawbacks.
As an example, a homeowner in Pottsville, Pa. in a letter to "Home and Shop Journal, Homeowner's Clinic" in the February 1993 Popular Mechanics, page 72 reported having a problem of water entering the dwelling space during a heavy rain. The problem was diagnosed as a break or blockage inside the vent pipe. The entry of the water into the vent-stack pipe posed a serious problem.
In addition, water entering the stack pipe is typically rainwater, requiring no sewage treatment. However, since it is directed to the sewage system the added rainwater adds to sewage treatment load. This is undesirable, particularly since many communities are faced with a lack of sewage capacity. It has been estimated that at least in some parts of the country, as many as 20 gallons a year is added to the sewage load from rainwater entering one unprotected stack pipe.
Finally, the conventional stack pipes are unattractive. Accordingly, it is the usual practice to install vent pipes on the rear side of a roof, so that the appearance of a building from the front is not deteriorated by the presence of the stack pipe vent. However, if the fixture requiring venting is in the front of the house, this means added expense in the form of both labor and materials to run the stack pipes to the rear of the buildings.
Accordingly, there remains a need in the art for an improved roof vent flashing which will prevent rainwater and debris from entering the pipe and is aesthetically acceptable to be placed on the front of a building.